U.S. patent application number 16/533509 was filed with the patent office on 2019-11-28 for methods of forming image sensor integrated circuit packages.
This patent application is currently assigned to SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC. The applicant listed for this patent is SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC. Invention is credited to Jui Yi CHIU.
Application Number | 20190363121 16/533509 |
Document ID | / |
Family ID | 55947356 |
Filed Date | 2019-11-28 |
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United States Patent
Application |
20190363121 |
Kind Code |
A1 |
CHIU; Jui Yi |
November 28, 2019 |
METHODS OF FORMING IMAGE SENSOR INTEGRATED CIRCUIT PACKAGES
Abstract
A method of forming image sensor packages may include performing
a molding process. Mold material may be formed either on a
transparent substrate in between image sensor dies, or on a
removable panel in between transparent substrates attached to image
sensor dies. Redistribution layers may be formed before or after
the molding process. Mold material may be formed after forming
redistribution layers so that the mold material covers the
redistribution layers. In these cases, holes may be formed in the
mold material to expose solder pads on the redistribution layers.
Alternatively, redistribution layers may be formed after the
molding process and the redistribution layers may extend over the
mold material. Image sensor dies may be attached to a glass or
notched glass substrate with dam structures. The methods of forming
image sensor packages may result in hermetic image sensor packages
that prevent exterior materials from reaching the image sensor.
Inventors: |
CHIU; Jui Yi; (Taichung
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC |
Phoenix |
AZ |
US |
|
|
Assignee: |
SEMICONDUCTOR COMPONENTS
INDUSTRIES, LLC
Phoenix
AZ
|
Family ID: |
55947356 |
Appl. No.: |
16/533509 |
Filed: |
August 6, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15459228 |
Mar 15, 2017 |
10418395 |
|
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16533509 |
|
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14586225 |
Dec 30, 2014 |
9634059 |
|
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15459228 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 2224/11 20130101;
H01L 2224/94 20130101; H01L 27/14687 20130101; H01L 27/14636
20130101; H01L 27/14618 20130101 |
International
Class: |
H01L 27/146 20060101
H01L027/146 |
Claims
1. A method of forming image sensor packages comprising: attaching
a plurality of dam structures to a transparent substrate; forming a
plurality of conductive vias in an image sensor wafer that
comprises first and second image sensor dies, wherein each of the
first and second image sensor dies has at least one conductive via
of the plurality of conductive vias; forming a plurality of
conductive layers on the first and second image sensor dies,
wherein each of the plurality of conductive layers is electrically
connected to a respective one of the plurality of conductive vias;
attaching the first image sensor die to at least a first dam
structure of the plurality of dam structures and attaching the
second image sensor die to at least a second dam structure of the
plurality of dam structures; performing a molding process, wherein
performing the molding process comprises forming a mold material
over the plurality of conductive layers; and cutting the mold
material to form first and second image sensor packages.
2. The method defined in claim 1, wherein attaching the first image
sensor die to at least the first dam structure and attaching the
second image sensor die to at least the second dam structure
comprises attaching the first image sensor die to at least the
first dam structure and attaching the second image sensor die to at
least the second dam structure after forming the plurality of
conductive layers on the first and second image sensor dies.
3. The method defined in claim 1, wherein performing the molding
process comprises forming the mold material in between the first
and second image sensor dies.
4. The method defined in claim 1, wherein the transparent substrate
has first and second opposing surfaces, wherein the first and
second dam structures are separated by a gap, and wherein
performing the molding process comprises forming the mold material
in the gap between the first and second dam structures and in
direct contact with the first surface of the transparent
substrate.
5. The method defined in claim 1, further comprising: forming vias
in the mold material over the plurality of conductive layers.
6. The method defined in claim 5, further comprising: forming
conductive material in the vias that directly contacts the
plurality of conductive layers.
7. The method defined in claim 5, further comprising: forming
solder balls in the vias that each directly contact at least one of
the plurality of conductive layers.
8. The method defined in claim 1, further comprising: before
attaching the first image sensor die to at least the first dam
structure and attaching the second image sensor die to at least the
second dam structure, separating the first and second image sensor
dies.
9. The method defined in claim 8, wherein separating the first and
second image sensor dies comprises cutting through the image sensor
wafer.
10. The method defined in claim 1, wherein cutting the mold
material to form the first and second image sensor packages
comprises cutting the mold material and the transparent substrate
to form first and second image sensor packages.
11. The method defined in claim 1, wherein the first dam structure
has a first side surface between third and fourth opposing
surfaces, wherein the second dam structure has a second side
surface between fifth and sixth opposing surfaces, and wherein
performing the molding process comprises forming the mold material
in direct contact with the first side surface and the second side
surface.
12. A method of forming image sensor packages comprising: attaching
a plurality of dam structures to a transparent substrate; forming a
plurality of conductive vias in an image sensor wafer that
comprises first and second image sensor dies, wherein each of the
first and second image sensor dies has at least one conductive via
of the plurality of conductive vias; forming a plurality of
conductive layers on the first and second image sensor dies,
wherein each of the plurality of conductive layers are electrically
and mechanically connected to a respective one of the plurality of
conductive vias; after forming the plurality of conductive layers
on the first and second image sensor dies, attaching the first
image sensor die to at least a first dam structure of the plurality
of dam structures and attaching the second image sensor die to at
least a second dam structure of the plurality of dam structures;
performing a molding process, wherein performing the molding
process comprises forming a mold material in between the first and
second image sensor dies and over the plurality of conductive
layers; forming vias in the mold material over the plurality of
conductive layers; forming solder balls in the vias that directly
contact the plurality of conductive layers; and cutting the mold
material to form first and second image sensor packages.
13. A method of forming image sensor packages comprising: attaching
at least first and second dam structures to a transparent
substrate, wherein the transparent substrate has first and second
opposing surfaces and wherein the first and second dam structures
are separated by a gap; forming a plurality of conductive vias in
an image sensor wafer that comprises first and second image sensor
dies, wherein each of the first and second image sensor dies has at
least one conductive via of the plurality of conductive vias;
separating the first and second image sensor dies; after separating
the first and second image sensor dies, attaching the first image
sensor die to the first dam structure and attaching the second
image sensor die to the second dam structure; performing a molding
process, wherein performing the molding process comprises forming a
mold material in between the first and second image sensor dies,
wherein attaching the first and second dam structures to the
transparent substrate comprises attaching the first and second dam
structures to the first surface of the transparent substrate and
wherein performing the molding process comprises forming the mold
material in the gap between the first and second dam structures and
in direct contact with the first surface of the transparent
substrate; and cutting the transparent substrate and the mold
material to form first and second image sensor packages.
14. The method defined in claim 13, further comprising: after
performing the molding process, forming a plurality of conductive
layers on the first and second image sensor dies, wherein each of
the plurality of conductive layers are electrically and
mechanically connected to a respective one of the plurality of
conductive vias; and forming a passivation layer over the
conductive layers.
15. The method defined in claim 14, wherein forming the plurality
of conductive layers on the first and second image sensor dies
comprises forming at least one conductive layer that extends onto
and directly contacts the mold material in between the first and
second image sensor dies.
16. The method defined in claim 13, further comprising: before
performing the molding process, forming a plurality of conductive
layers on the first and second image sensor dies, wherein each of
the plurality of conductive layers are electrically and
mechanically connected to a respective one of the plurality of
conductive vias.
17. The method defined in claim 16, wherein performing the molding
process comprises forming the mold material over the plurality of
conductive layers.
18. The method defined in claim 17, further comprising: forming
vias in the mold material over the plurality of conductive layers;
and forming solder balls in the vias that directly contact the
plurality of conductive layers.
19. The method defined in claim 13, wherein the first dam structure
has a first side surface between third and fourth opposing
surfaces, wherein the second dam structure has a second side
surface between fifth and sixth opposing surfaces, and wherein
performing the molding process comprises forming the mold material
in direct contact with the first side surface and the second side
surface.
20. The method defined in claim 13, wherein separating the first
and second image sensor dies comprises cutting through the image
sensor wafer.
Description
[0001] This application is a division of patent application Ser.
No. 15/459,228, filed Mar. 15, 2017, which is a division of patent
application Ser. No. 14/586,225, filed Dec. 30, 2014, which are
hereby incorporated by reference herein in their entireties. This
application claims the benefit of and claims priority to patent
application Ser. No. 15/459,228, filed Mar. 15, 2017, and patent
application Ser. No. 14/586,225, filed Dec. 30, 2014.
BACKGROUND
[0002] This relates generally to imaging systems and, more
particularly, to imaging systems having image sensor integrated
circuit packages.
[0003] Modern electronic devices such as cellular telephones,
cameras, and computers often use digital image sensors. Imagers
(i.e., image sensors) often include a two-dimensional array of
image sensing pixels. Each pixel typically includes a
photosensitive element such as a photodiode that receives incident
photons (light) and converts the photons into electrical
signals.
[0004] In a typical arrangement, an image sensor die includes an
image sensor integrated circuit formed on a front surface of the
image sensor die and electrical contacts (e.g., a grid of solder
balls) formed on a rear surface of the image sensor die.
Through-silicon vias are used to electrically connect the image
sensor integrated circuit on the front surface of the image sensor
die to the electrical contacts on the rear surface of the image
sensor die. The image sensor die is then mechanically and
electrically coupled to a printed circuit board by soldering the
electrical contacts on the rear surface of the image sensor die to
the printed circuit board.
[0005] There are a number of disadvantages associated with this
type of packaging arrangement. In particular, the image sensing
pixels and other internal electronic components may not be
sufficiently protected from external elements such as dirt, dust,
and water. The performance of the image sensing pixels and the
image sensor as a whole may be compromised if external elements are
allowed to enter an image sensor package. For example, water that
leaks into an image sensor package may decrease performance of the
image sensor or cease the image sensor from functioning
entirely.
[0006] It would therefore be desirable to provide improved ways of
forming image sensor integrated circuit packages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a diagram of an illustrative imaging system having
a camera module that includes one or more image sensors in
accordance with an embodiment of the present invention.
[0008] FIG. 2 is a diagram of an illustrative image sensor wafer
having multiple image sensors in accordance with an embodiment of
the present invention.
[0009] FIG. 3 is a cross-sectional diagram of an illustrative
method for forming image sensor packages including a molding
process and subsequently forming a redistribution layer in
accordance with an embodiment of the present invention.
[0010] FIG. 4 is a cross-sectional diagram of an illustrative
method for forming image sensor packages including forming a
redistribution layer and subsequently performing a molding process
in accordance with an embodiment of the present invention.
[0011] FIG. 5 is a cross-sectional diagram of an illustrative
method for forming image sensor packages including using a
removable panel in accordance with an embodiment of the present
invention.
[0012] FIG. 6 is a cross-sectional diagram of an illustrative
method for forming image sensor packages including using a notched
substrate and a removable panel in accordance with an embodiment of
the present invention.
[0013] FIG. 7 is a cross-sectional diagram of an illustrative
method for forming image sensor packages including using a notched
substrate and a removable panel in accordance with an embodiment of
the present invention.
[0014] FIG. 8 is a block diagram of an illustrative processor
system employing the embodiments of FIGS. 1-7 in accordance with an
embodiment of the present invention.
DETAILED DESCRIPTION
[0015] Electronic devices such as digital cameras, computers,
cellular telephones, and other electronic devices include image
sensors that gather incoming image light to capture an image. An
image sensor may include an array of imaging pixels. The imaging
pixels may include photosensitive elements such as photodiodes that
convert the incoming image light into image signals. Image sensors
may have any number of pixels (e.g., hundreds or thousands or
more). A typical image sensor may, for example, have hundreds of
thousands or millions of pixels (e.g., megapixels). Image sensors
may include control circuitry such as circuitry for operating the
imaging pixels and readout circuitry for reading out image signals
corresponding to the electric charge generated by the
photosensitive elements.
[0016] FIG. 1 is a diagram of an illustrative electronic device
that uses one or more image sensors to capture images. Electronic
device 10 of FIG. 1 may be a portable electronic device such as a
camera, a cellular telephone, a video camera, or other imaging
device that captures digital image data. Camera module 12 may be
used to convert incoming light into digital image data. Camera
module 12 may include one or more lenses 14 and one or more
corresponding image sensors 16. During image capture operations,
light from a scene may be focused onto image sensor 16 using lens
14. Image sensor 16 may provide corresponding digital image data to
processing circuitry 18. If desired, camera module 12 may be
provided with an array of lenses 14 and an array of corresponding
image sensors 16. Each image sensor 16 may include an image pixel
array 40 with an array of image sensor pixels 15. Image sensors 16
may include one or more backside illumination (BSI) image sensors
and/or one or more front side illumination (FSI) image sensors.
[0017] Processing circuitry 18 may include one or more integrated
circuits (e.g., image processing circuits, microprocessors, storage
devices such as random-access memory and non-volatile memory, etc.)
and may be implemented using components that are separate from
camera module 12 and/or that form part of camera module 12 (e.g.,
circuits that form part of an integrated circuit that includes
image sensors 16 or an integrated circuit within module 12 that is
associated with image sensors 16). Image data that has been
captured by camera module 12 may be processed and stored using
processing circuitry 18. Processed image data may, if desired, be
provided to external equipment (e.g., a computer or other device)
using wired and/or wireless communications paths coupled to
processing circuitry 18.
[0018] FIG. 2 shows an illustrative image sensor wafer 160 having a
plurality of image sensor dies 16 (e.g., sensor #1, sensor #2,
sensor #3, etc.). Each image sensor die 16 may include an array of
image sensor pixels operable to produce image data (e.g., still or
video data). During wafer dicing operations, wafer 160 may be cut
along lines 66 to dice wafer 160 into individual image sensor dies
16. A singulated image sensor die may form part of a camera module
that includes a single image sensor die 16 or may form part of an
array camera that includes an array of image sensor dies 16.
[0019] In arrangements where image sensor dies 16 are used in an
array camera, image sensor dies 16 need not be singulated from the
other image sensor dies 16 in the array camera. For example, sensor
#1, sensor #2, and sensor #3 may be singulated from the remaining
image sensors in wafer 160 but may, if desired, remain together as
one piece (e.g., a single image sensor die with three image pixel
arrays). This is, however, merely illustrative. If desired, image
sensors that form part of an array camera may be singulated into
individual die (with one image pixel array per image sensor die)
and then mounted adjacent to one another on a common printed
circuit board in the array camera.
[0020] Image sensor 16 may be a backside illumination image sensor
or may be a front side illumination image sensor. In a front side
illumination image sensor, circuitry such as metal interconnect
circuitry may be interposed between the microlens array and the
photosensitive regions of the image sensor. In a backside
illumination image sensor, the photosensitive regions are
interposed between the microlens array and the metal interconnect
circuitry of the image sensor.
[0021] FIG. 3 shows an illustrative method 100 for making image
sensor packages that include image sensors such as image sensor 16.
At step 102, a substrate 116 and a wafer 118 may be provided. Wafer
118 may be made of silicon and may include one or more pixel arrays
122. Each pixel array may correspond to a different sensor. For
example, a first pixel array may be used in a first image sensor
such as sensor #1 in FIG. 2, and a second pixel array may be used
in a second image sensor such as sensor #2 in FIG. 2. In FIG. 3,
wafer 118 is shown with two pixel arrays, but this example is
merely illustrative. Wafer 118 may have one pixel array, two pixel
arrays, ten pixel arrays, hundreds of pixel arrays, or more than
hundreds of pixel arrays. Wafer 118 may include an image sensor
integrated circuit or multiple image sensor integrated circuits on
the same side of the wafer as pixel arrays 122.
[0022] Substrate 116 may be formed from a transparent glass sheet,
a clear plastic layer, or other suitable transparent member. If
desired, substrate 116 may be non-transparent or may be only
partially transparent. For example, substrate 116 may transmit
certain ranges of wavelengths while blocking other ranges of
wavelengths, if desired. In arrangements where image sensor 16 is
used for analyzing fluids (e.g., for capturing images of a
substance during a photochemical reaction), it may desirable for
substrate 116 to be completely or partially opaque (as an example).
In general, substrate 116 may have any desired transmission
spectrum. Arrangements where substrate 116 is transparent are
sometimes described herein as an illustrative example. Depending on
the process, substrate 116 may be in wafer form or panel form.
[0023] At step 104, dams 120 are attached to substrate 116. Dams
120 may be attached to substrate 116 using any desired methods or
materials. For example, dams 120 may be attached to substrate 116
using adhesive, glue, epoxy, polymer, or any other desired
material. In certain embodiments, dams 120 may be formed from an
adhesive material. Also at step 104, vias 124 may be formed in
wafer 118. Vias 124 may provide a vertical electrical connection
that passes completely through wafer 118. In embodiments where
wafer 118 is made of silicon, vias 124 may be known as
through-silicon vias (TSV). Vias 124 may be electrically connected
to an image sensor integrated circuit.
[0024] Dams 120 may be formed from any desired material and have
any desired dimensions. Dams 120 may, for example, be a
photodefinable adhesive such as a dry film adhesive that can be
applied and patterned using photolithographic techniques. In FIG.
3, substrate 116 is shown with four attached dams. This example is
merely illustrative. Substrate 116 may be attached to one dam, two
dams, ten dams, hundreds of dams, or more than hundreds of dams.
Substrate 116 may be attached to any desired number of dams for
each sensor die in wafer 118. For example, substrate 116 may be
attached to two dams for each sensor die in wafer 118.
[0025] At step 106, wafer 118 may be sawed to form sensor dies 126
and 128. Wafer 118 may be sawed in a manner similar to that
described in FIG. 2. Each sensor die may be attached to dams 120.
Each sensor die may be attached to two dams, with one dam on each
side of the sensor die. The sensor dies may be attached to the dams
using adhesive, glue, epoxy, polymer, or any other desired
material. In embodiments where dams 120 are made of an adhesive
material, the sensor dies may be attached to the dams without using
an additional material.
[0026] At step 108, a molding process may be performed to fill in
the gap between sensor dies. Mold 130 may fill in the gap between
sensor dies 126 and 128 and may fill the areas to the sides of
sensor dies 126 and 128. As shown in FIG. 3, sensor die 126 may
have a side closest to substrate 116 that is attached to dams 120.
The side that is furthest from substrate 116, which may
subsequently be referred to as the top surface, may be left exposed
during the molding process. Consequently, the portions of vias 124
on the top surface may also be left exposed during the molding
process. Dams 120 may prevent mold 130 from reaching pixel arrays
122. The molding process at step 108 may consist of dispensing a
liquid compound, compression molding, or any other desired molding
process. In embodiments where a liquid compound is used for the
molding, the liquid compound may be poured in between each sensor
die. The liquid compound may fill in all areas without penetrating
through dams 120. The liquid compound may later be cured to provide
a hermetic seal that prevents outside materials from reaching pixel
array 122. In embodiments where compression molding is used, a mold
material such as plastic may be heated at a suitable temperature
for a suitable length of time. The mold material may then be
compressed in between sensor dies and left to cure, effectively
providing a hermetic seal in between the sensor dies.
[0027] At step 110, vias 124 may be provided with redistribution
layers 125. While vias may extend vertically through dies 126 and
128, redistribution layers 125 may be conductive layers that
connect to vias 124 and extend horizontally across the top surface
of dies 126 and 128. Redistribution layers 125 may extend
horizontally past the edge of dies 126 and 128 and onto mold 130.
Redistribution layers 125 may be formed with a seed layer of
conductive material such as a metal. The seed layer may be
titanium, titanium-tungsten, copper, or any other desired
conductive material. Redistribution layers 125 may then have a
conductive material such as a metal plated on the seed layer. The
plated conductive material may be copper, nickel, aluminum, or any
other desired conductive material. Passivation layer 132 may be
formed to protect redistribution layers 125. Passivation layer 132
may be formed from a polymer, polyimide (PI), polybenzoxazole
(PBO), benzocyclobuten (BCB), solder mask material, or any other
desired material. Redistribution layers 125 may extend the amount
of area available for forming solder connections. Redistribution
layers 125 may have solder pads that may later receive solder to
form mechanical and electrical connections to a printed circuit
board. The solder pads may be tin-lead plated copper pads, silver
plated copper pads, gold plated copper pads, or any other desired
type of solder pad.
[0028] At step 112, solder 134 may be formed on redistribution
layers 125. Solder balls 134 are formed on the top surface of
silicon dies 126 and 128. In certain embodiments, solder balls 134
may be used to electrically connect through-silicon vias 124 to
bond pads on a printed circuit board. Solder balls 134 may be
located on solder pads on redistribution layers 125.
[0029] At step 114, substrate 116 and mold 130 may be cut to
separate dies 126 and 128. The resulting image sensor package 136
uses mold 130 and passivation layer 132 to ensure a durable
hermetic package. Image sensor package 136 may have opposing top
and bottom surfaces with first and second opposing side surfaces
connecting the top and bottom surfaces. The entire bottom surface
of image sensor package 136 may be formed from substrate 116. The
top surface of image sensor package 136 may have portions that are
formed from redistribution layers 125, portions that are formed
from passivation layer 132, and portions that are formed from
solder 134. The side surfaces of image sensor package 136 may have
portions that are formed from substrate 116, portions that are
formed from mold material 130, and portions that are formed from
passivation layer 132.
[0030] FIG. 4 shows an illustrative method 200 for making image
sensor packages including image sensors such as image sensor 16. At
step 202, a substrate 216 and wafer 218 may be provided. Wafer 218
may be made of silicon and may include one or more pixel arrays
222. Each pixel array may correspond to a different sensor. For
example, a first pixel array may be used in a first image sensor
such as sensor #1 in FIG. 2, and a second pixel array may be used
in a second image sensor such as sensor #2 in FIG. 2. In FIG. 4,
wafer 218 is shown with two pixel arrays, but this example is
merely illustrative. Wafer 218 may have one pixel array, two pixel
arrays, ten pixel arrays, hundreds of pixel arrays, or more than
hundreds of pixel arrays. Wafer 218 may include an image sensor
integrated circuit or multiple image sensor integrated circuits on
the same side of the wafer as pixel arrays 222.
[0031] Substrate 216 may be formed from a transparent glass sheet,
a clear plastic layer, or other suitable transparent member. If
desired, substrate 216 may be non-transparent or may be only
partially transparent. For example, substrate 216 may transmit
certain ranges of wavelengths while blocking other ranges of
wavelengths, if desired. In arrangements where image sensor 16 is
used for analyzing fluids (e.g., for capturing images of a
substance during a photochemical reaction), it may desirable for
substrate 216 to be completely or partially opaque (as an example).
In general, substrate 216 may have any desired transmission
spectrum. Arrangements where substrate 216 is transparent are
sometimes described herein as an illustrative example.
[0032] At step 204, dams 220 are attached to substrate 216. Dams
220 may be attached to substrate 216 using any desired methods or
materials. For example, dams 220 may be attached to substrate 216
using adhesive, glue, epoxy, polymer, or any other desired
material. Also at step 204, vias 224 may be formed in wafer 218.
Vias 224 may provide a vertical electrical connection that passes
completely through wafer 218. In embodiments where wafer 218 is
made of silicon, vias 224 may be known as through-silicon vias
(TSV). Vias 224 may be electrically connected to an image sensor
integrated circuit.
[0033] At step 204, vias 224 may be provided with redistribution
layers 225. While vias 224 may extend vertically through waver 218,
redistribution layers 225 may be conductive layers that connect to
vias 224 and extend horizontally across the top surface of wafer
218. Redistribution layers 225 may be formed with a seed layer of
conductive material such as a metal. The seed layer may be
titanium, titanium-tungsten, copper, or any other desired
conductive material. Redistribution layers 225 may then have a
conductive material such as a metal plated on the seed layer. The
plated conductive material may be copper, nickel, aluminum, or any
other desired conductive material. Redistribution layers 225 may
extend the amount of area available for forming solder connections.
Redistribution layers 225 may have solder pads for forming solder
connections. The solder pads may be tin-lead plated copper pads,
silver plated copper pads, gold plated copper pads, or any other
desired type of solder pad.
[0034] Dams 220 may be formed from any desired material and have
any desired dimensions. In FIG. 4, substrate 216 is shown with four
attached dams. This example is merely illustrative. Substrate 216
may be attached to one dam, two dams, ten dams, hundreds of dams,
or more than hundreds of dams. Substrate 216 may be attached to any
desired number of dams for each sensor die in wafer 218. For
example, substrate 216 may be attached to two dams for each sensor
die in wafer 218.
[0035] At step 206, wafer 218 may be sawed to form sensor dies 226
and 228. Wafer 218 may be sawed in a manner similar to that
described in FIG. 2. Each sensor die may be attached to dams 220.
Each sensor die may be attached to two dams, with one dam on each
side of the sensor die. The sensor dies may be attached to the dams
using adhesive, glue, epoxy, polymer, or any other desired
material. In certain embodiments, dams 220 may be formed from an
adhesive material. In embodiments where dams 220 are formed from an
adhesive material, the transparent substrate may be attached to the
dams without using an additional material. Similarly, the sensor
dies may be attached to the dams without using an additional
material.
[0036] At step 208, a molding process may be performed to
encapsulate the sensor dies and fill in the gaps between the sensor
dies. Mold 230 may fill in the gap between sensor dies 226 and 228
and may fill the areas to the sides of sensor dies 226 and 228. As
shown in FIG. 4, sensor die 226 may have a side closest to
substrate 216 that is attached to dams 220. The side that is
furthest from substrate 216, which may subsequently be referred to
as the top surface, may be entirely covered by mold 230 during the
molding process. Similarly, the redistribution layers 225 may be
entirely covered by mold 230 during the molding process. The mold
may have a planar top surface after step 208. Dams 220 may prevent
mold 230 from reaching pixel arrays 222.
[0037] The molding process at step 208 may consist of dispensing a
liquid compound, compression molding, or any other desired molding
process. In embodiments where a liquid compound is used for the
molding, the liquid compound may be poured in between each sensor
die. The liquid compound may fill in all areas without penetrating
through dams 220. The liquid compound may later be cured to provide
a hermetic seal that prevents outside materials from reaching pixel
array 222. In embodiments where compression molding is used, a mold
material such as plastic may be heated at a suitable temperature
for a suitable length of time. The mold material may then be
compressed in between sensor dies and left to cure, effectively
providing a hermetic seal in between the sensor dies.
[0038] At step 210, mold vias 232 may be formed on the top surface
of mold 230. The mold vias 232 may expose solder pads on the top
surfaces of the redistributed layers 225. Mold vias 232 may be
formed using a laser drilling process or any other desired process.
In the laser drilling process, a laser is used to make vias 232 in
mold 230.
[0039] At step 212, solder 234 may be formed in mold vias 232 on
redistribution layers 225. Solder balls 234 are formed on the top
surface of silicon dies 226 and 228. In certain embodiments, solder
balls 234 may be used to electrically connect through-silicon vias
224 to bond pads on a printed circuit board. Solder balls 234 may
be located on solder pads on redistribution layers 225.
[0040] At step 214, substrate 216 and mold 230 may be cut to
separate dies 226 and 228. The resulting image sensor package 236
uses mold 230 to ensure a durable hermetic package. Image sensor
package 236 may have opposing top and bottom surfaces with first
and second opposing side surfaces connecting the top and bottom
surfaces. The entire bottom surface of image sensor package 236 may
be formed from substrate 216. The top surface of image sensor
package 236 may have portions that are formed from mold material
230 and portions that are formed from solder 134. The side surfaces
of image sensor package 236 may have portions that are formed from
substrate 216 and portions that are formed from mold material
230.
[0041] FIG. 5 shows an illustrative method 300 for making image
sensor packages including image sensors such as image sensor 16. At
step 302, a substrate 317 and wafer 318 may be provided. Wafer 318
may be made of silicon and may include one or more pixel arrays
322. Each pixel array may correspond to a different sensor. For
example, a first pixel array may be used in a first image sensor
such as sensor #1 in FIG. 2, and a second pixel array may be used
in a second image sensor such as sensor #2 in FIG. 2. In FIG. 5,
wafer 318 is shown with two pixel arrays, but this example is
merely illustrative. Wafer 318 may have one pixel array, two pixel
arrays, ten pixel arrays, hundreds of pixel arrays, or more than
hundreds of pixel arrays. Wafer 318 may include an image sensor
integrated circuit or multiple image sensor integrated circuits on
the same side of the wafer as pixel arrays 322.
[0042] Substrate 317 may be formed from a transparent glass sheet,
a clear plastic layer, or other suitable transparent member. If
desired, substrate 317 may be non-transparent or may be only
partially transparent. For example, substrate 317 may transmit
certain ranges of wavelengths while blocking other ranges of
wavelengths, if desired. In arrangements where image sensor 16 is
used for analyzing fluids (e.g., for capturing images of a
substance during a photochemical reaction), it may desirable for
substrate 317 to be completely or partially opaque (as an example).
In general, substrate 317 may have any desired transmission
spectrum. Arrangements where substrate 317 is transparent are
sometimes described herein as an illustrative example.
[0043] At step 304, dams 320 are attached to substrate 317. Dams
320 may be attached to substrate 317 using any desired methods or
materials. For example, dams 320 may be attached to substrate 317
using adhesive, glue, epoxy, polymer, or any other desired
material. Also at step 304, vias 324 may be formed in wafer 318.
Vias 324 may provide a vertical electrical connection that passes
completely through wafer 318. In embodiments where wafer 318 is
made of silicon, vias 324 may be known as through-silicon vias
(TSV). Vias 324 may be electrically connected to an image sensor
integrated circuit.
[0044] At step 304, vias 324 may be provided with redistribution
layers 325. While vias 324 may extend vertically through waver 318,
redistribution layers 325 may be conductive layers that connect to
vias 324 and extend horizontally across the top surface of wafer
318. Redistribution layers 325 may be formed with a seed layer of
conductive material such as a metal. The seed layer may be
titanium, titanium-tungsten, copper, or any other desired
conductive material. Redistribution layers 325 may then have a
conductive material such as a metal plated on the seed layer. The
plated conductive material may be copper, nickel, aluminum, or any
other desired conductive material. Redistribution layers 325 may
extend the amount of area available for forming solder connections.
Redistribution layers 325 may have solder pads for forming solder
connections. The solder pads may be tin-lead plated copper pads,
silver plated copper pads, gold plated copper pads, or any other
desired type of solder pad.
[0045] Dams 320 may be formed from any desired material and have
any desired dimensions. In FIG. 5, substrate 317 is shown with four
attached dams. This example is merely illustrative. Substrate 317
may be attached to one dam, two dams, ten dams, hundreds of dams,
or more than hundreds of dams. Substrate 317 may be attached to any
desired number of dams for each sensor die in wafer 318. For
example, substrate 317 may be attached to two dams for each sensor
die in wafer 318.
[0046] At step 306, wafer 318 may be attached to dams 320. Wafer
318 may be attached to dams 320 such that each sensor die is
attached to two dams, with one dam on each side of the sensor die.
Wafer 318 may be attached to the dams using adhesive, glue, epoxy,
polymer, or any other desired material. At step 306, wafer 318 has
yet to be separated into individual sensor dies. In certain
embodiments, dams 320 may be formed from an adhesive material. In
embodiments where dams 320 are formed from an adhesive material,
the transparent substrate may be attached to the dams without using
an additional material. Similarly, the sensor dies may be attached
to the dams without using an additional material. In certain
embodiments, substrate 317 may be a wafer that proceeds in a wafer
bonding process with wafer 318.
[0047] At step 308, wafer 318 and substrate 317 may be separated to
form sensor dies 326 and 328 which each are attached to a separate
portion of substrate 317. For example, sensor die 326 may be
attached to portion 337 of substrate 317 and sensor die 328 may be
attached to portion 338 of substrate 317. After being separated,
substrate portions 337 and 338 may be attached to panel 329. Sensor
dies 326 and 328 may be separated by sawing, cutting, or any other
desired method. Panel 329 may be temporarily attached to substrate
portions 337 and 338. Panel 329 may be made of a polymer or any
other desired material. Depending on the process, panel 329 may be
in wafer form or panel form.
[0048] At step 310, a molding process may be performed to
encapsulate the sensor dies and fill in the gaps between the sensor
dies. Mold 330 may fill in the gap between sensor dies 326 and 328
and may fill the areas to the sides of sensor dies 326 and 328.
Similarly, mold 330 may fill in the gap between substrate portions
337 and 338 and may fill the areas to the sides of substrate
portions 337 and 338. As shown in FIG. 5, sensor die 326 may have a
side closest to substrate 337 that is attached to dams 320. The
side that is furthest from substrate 337, which may subsequently be
referred to as the top surface, may be entirely covered by mold 330
during the molding process. Similarly, the redistribution layers
325 may be entirely covered by mold 330 during the molding process.
The mold may have a planar top surface after step 310. Dams 320 may
prevent mold 330 from reaching pixel arrays 322.
[0049] The molding process at step 310 may consist of dispensing a
liquid compound, compression molding, or any other desired molding
process. In embodiments where a liquid compound is used for the
molding, the liquid compound may be poured in between each sensor
die. The liquid compound may fill in all areas without penetrating
through dams 320. The liquid compound may later be cured to provide
a hermetic seal that prevents outside materials from reaching pixel
array 322. In embodiments where compression molding is used, a mold
material such as plastic may be heated at a suitable temperature
for a suitable length of time. The mold material may then be
compressed in between sensor dies and left to cure, effectively
providing a hermetic seal in between the sensor dies.
[0050] At step 312, mold vias 332 may be formed on the top surface
of mold 330. The mold vias 332 may expose solder pads on the top
surfaces of the redistributed layers 325. Mold vias 332 may be
formed using a laser drilling process or any other desired process.
In the laser drilling process, a laser is used to make vias 332 in
mold 330.
[0051] At step 314, solder 334 may be formed in mold vias 332 on
redistribution layers 325. Solder balls 334 are formed on the top
surface of silicon dies 326 and 328. In certain embodiments, solder
balls 334 may be used to electrically connect through-silicon vias
324 to bond pads on a printed circuit board. Solder balls 334 may
be located on solder pads on redistribution layers 325.
[0052] At step 316, panel 329 may be removed. Panel 329 may be
removed using any desired process. Mold 330 may then be cut to
separate dies 326 and 328. Image sensor package 336 may have
opposing top and bottom surfaces with first and second opposing
side surfaces connecting the top and bottom surfaces.
[0053] In certain embodiments, image sensor package 336 may be
diced such that no molding material remains on the left and right
sides of sensor die 326 or substrate portion 337. In these
embodiments, the entire bottom surface of image sensor package 336
may be formed from substrate portion 337. The top surface of image
sensor package 336 may be have portions that are formed from mold
material 330 and portions that are formed from solder 334. The side
surfaces of image sensor package 336 may have portions that are
formed from substrate 337, portions that are formed from dams 320,
portions that are formed from sensor die 326, portions that are
formed from redistribution layers 325, and portions that are formed
from mold material 330.
[0054] In certain embodiments, only one cut may be made in between
sensor dies 326 and 328 (e.g., FIG. 5). In these embodiments, the
bottom surface of image sensor package 336 may have portions formed
from substrate portion 337 and portions formed from mold material
330. The top surface of image sensor package 336 may be have
portions that are formed from mold material 330 and portions that
are formed from solder 334. The side surfaces may be formed
entirely from mold material 330.
[0055] FIG. 6 shows an illustrative method 400 for making image
sensor packages including image sensors such as image sensor 16. At
step 402, a notched substrate 417 and a wafer 418 may be provided.
Wafer 418 may be made of silicon and may include one or more pixel
arrays 422. Each pixel array may correspond to a different sensor.
For example, a first pixel array may be used in a first image
sensor such as sensor #1 in FIG. 2, and a second pixel array may be
used in a second image sensor such as sensor #2 in FIG. 2. In FIG.
6, wafer 418 is shown with two pixel arrays, but this example is
merely illustrative. Wafer 418 may have one pixel array, two pixel
arrays, ten pixel arrays, hundreds of pixel arrays, or more than
hundreds of pixel arrays. Wafer 418 may include an image sensor
integrated circuit or multiple image sensor integrated circuits on
the same side of the wafer as pixel arrays 422. Depending on the
process, notched substrate 417 may be in wafer form or panel
form.
[0056] Notched substrate 417 may be formed from a transparent glass
sheet, a clear plastic layer, or other suitable transparent member.
If desired, notched substrate 417 may be non-transparent or may be
only partially transparent. For example, notched substrate 417 may
transmit certain ranges of wavelengths while blocking other ranges
of wavelengths, if desired. In arrangements where image sensor 16
is used for analyzing fluids (e.g., for capturing images of a
substance during a photochemical reaction), it may desirable for
notched substrate 417 to be completely or partially opaque (as an
example). In general, notched substrate 417 may have any desired
transmission spectrum. Arrangements where notched substrate 417 is
transparent are sometimes described herein as an illustrative
example.
[0057] Notched substrate 417 may have a first thickness 440 at the
portions without notches. Notched substrate 417 may have a second
thickness 442 at the notched portions. The second thickness may be
less than the first thickness. The first and second thicknesses may
be less than a micron, less than a millimeter, less than a
centimeter, greater than a centimeter, or any other desired
thickness. The notches in notched substrate 417 may be formed by
wet etching, dry etching, a laser grooving process or any other
desired process.
[0058] At step 404, dams 420 are attached to notched substrate 417.
Dams 420 may be attached to notched substrate 417 using any desired
methods or materials. For example, dams 420 may be attached to
notched substrate 417 using adhesive, glue, epoxy, polymer, or any
other desired material. Also at step 404, vias 424 may be formed in
wafer 418. Vias 424 may provide a vertical electrical connection
that passes completely through wafer 418. In embodiments where
wafer 418 is made of silicon, vias 424 may be known as
through-silicon vias (TSV). Vias 424 may be electrically connected
to an image sensor integrated circuit.
[0059] Dams 420 may be formed from any desired material and have
any desired dimensions. In FIG. 6, notched substrate 417 is shown
with four attached dams. This example is merely illustrative.
Notched substrate 417 may be attached to one dam, two dams, ten
dams, hundreds of dams, or more than hundreds of dams. Substrate
417 may be attached to any desired number of dams for each sensor
die in wafer 418. For example, substrate 417 may be attached to two
dams for each sensor die in wafer 418.
[0060] At step 406, wafer 418 may be attached to dams 420. Wafer
418 may be attached to dams 420 such that each sensor die is
attached to two dams, with one dam on each side of the sensor die.
Wafer 418 may be attached to the dams using adhesive, glue, epoxy,
polymer, or any other desired material. At step 406, wafer 418 has
yet to be separated into individual sensor dies. In certain
embodiments, dams 420 may be formed from an adhesive material. In
embodiments where dams 420 are formed from an adhesive material,
the transparent substrate may be attached to the dams without using
an additional material. Similarly, the sensor dies may be attached
to the dams without using an additional material.
[0061] At step 408, wafer 418 and notched substrate 417 may be
separated to form sensor dies 426 and 428 which each are attached
to a separate portion of notched substrate 417. For example, sensor
die 426 may be attached to portion 437 of notched substrate 417 and
sensor die 428 may be attached to portion 438 of notched substrate
417. After being separated, substrate portions 437 and 438 may be
attached to panel 429. Sensor dies 426 and 428 and substrate
portions 437 and 438 may be separated by sawing, cutting, or any
other desired method. As shown in FIG. 6, substrate 417 may be cut
at a notched portion with a thickness 442. The smaller thickness at
the notched portion makes cutting substrate 417 easier. Panel 429
may be temporarily attached to substrate portions 437 and 438.
Panel 429 may be made of a polymer or any other desired material.
Depending on the process, panel 429 may be in wafer form or panel
form.
[0062] At step 410, a molding process may be performed to fill in
the gaps between the sensor dies. Mold 430 may fill in the gap
between sensor dies 426 and 428 and may fill the areas to the sides
of sensor dies 426 and 428. Similarly, mold 430 may fill in the gap
between substrate portions 437 and 438 and may fill the areas to
the sides of substrate portions 437 and 438. As shown in FIG. 6,
sensor die 426 may have a side closest to substrate 437 that is
attached to dams 420. The side that is furthest from substrate 437,
which may subsequently be referred to as the top surface, may be
left exposed during the molding process. Consequently, the portions
of vias 424 on the top surface may also be left exposed during the
molding process. Dams 420 may prevent mold 430 from reaching pixel
arrays 422.
[0063] The molding process at step 410 may consist of dispensing a
liquid compound, compression molding, or any other desired molding
process. In embodiments where a liquid compound is used for the
molding, the liquid compound may be poured in between each sensor
die. The liquid compound may fill in all areas without penetrating
through dams 420. The liquid compound may later be cured to provide
a hermetic seal that prevents outside materials from reaching pixel
array 422. In embodiments where compression molding is used, a mold
material such as plastic may be heated at a suitable temperature
for a suitable length of time. The mold material may then be
compressed in between sensor dies and left to cure, effectively
providing a hermetic seal in between the sensor dies.
[0064] At step 412, vias 424 may be provided with redistribution
layers 425. While vias may extend vertically through dies 426 and
428, redistribution layers 425 may be conductive layers that
connect to vias 424 and extend horizontally across the top surface
of dies 426 and 428. Redistribution layers 425 may extend
horizontally past the edge of dies 426 and 428 and onto mold 430.
Redistribution layers 425 may be formed with a seed layer of
conductive material such as a metal. The seed layer may be
titanium, titanium-tungsten, copper, or any other desired
conductive material. Redistribution layers 425 may then have a
conductive material such as a metal plated on the seed layer. The
plated conductive material may be copper, nickel, aluminum, or any
other desired conductive material. Redistribution layers 425 may
extend the amount of area available for forming solder connections.
Redistribution layers 425 may have solder pads for forming solder
connections. The solder pads may be tin-lead plated copper pads,
silver plated copper pads, gold plated copper pads, or any other
desired type of solder pad.
[0065] At step 414, solder 434 may be formed on redistribution
layers 425. Solder balls 434 are formed on the top surface of
silicon dies 426 and 428. In certain embodiments, solder balls 434
may be used to electrically connect vias 424 to bond pads on a
printed circuit board. Solder balls 434 may be located on solder
pads on redistribution layers 425.
[0066] At step 416, panel 429 may be removed. Panel 429 may be
removed using any desired process. Mold 430 may then be cut to
separate dies 426 and 428. Image sensor package 436 may have
opposing top and bottom surfaces with first and second opposing
side surfaces connecting the top and bottom surfaces. In certain
embodiments, only one cut may be made in between sensor dies 426
and 428. In these embodiments, the bottom surface of image sensor
package 436 may have portions formed from substrate portion 437 and
portions formed from mold material 430. The top surface of image
sensor package 436 may be have portions that are formed from mold
material 430, portions that are formed from redistribution layers
425, and portions that are formed from solder 434. The side
surfaces may be formed entirely from mold material 430.
[0067] FIG. 7 shows an illustrative method 500 for making image
sensor packages including image sensors such as image sensor 16. At
step 502, a notched substrate 517 and a wafer 518 may be provided.
Wafer 518 may be made of silicon and may include one or more pixel
arrays 522. Each pixel array may correspond to a different sensor.
For example, a first pixel array may be used in a first image
sensor such as sensor #1 in FIG. 2, and a second pixel array may be
used in a second image sensor such as sensor #2 in FIG. 2. In FIG.
7, wafer 518 is shown with two pixel arrays, but this example is
merely illustrative. Wafer 518 may have one pixel array, two pixel
arrays, ten pixel arrays, hundreds of pixel arrays, or more than
hundreds of pixel arrays. Wafer 518 may include an image sensor
integrated circuit or multiple image sensor integrated circuits on
the same side of the wafer as pixel arrays 522. Depending on the
process, notched substrate 517 may be in wafer form or panel
form.
[0068] Notched substrate 517 may be formed from a transparent glass
sheet, a clear plastic layer, or other suitable transparent member.
If desired, notched substrate 517 may be non-transparent or may be
only partially transparent. For example, notched substrate 517 may
transmit certain ranges of wavelengths while blocking other ranges
of wavelengths, if desired. In arrangements where image sensor 16
is used for analyzing fluids (e.g., for capturing images of a
substance during a photochemical reaction), it may desirable for
notched substrate 517 to be completely or partially opaque (as an
example). In general, notched substrate 517 may have any desired
transmission spectrum. Arrangements where notched substrate 517 is
transparent are sometimes described herein as an illustrative
example.
[0069] Notched substrate 517 may have a first thickness 540 at the
portions without notches. Notched substrate 517 may have a second
thickness 542 at the notched portions. The second thickness may be
less than the first thickness. The first and second thicknesses may
be less than a micron, less than a millimeter, less than a
centimeter, greater than a centimeter, or any other desired
thickness. The notches in notched substrate 417 may be formed by
wet etching, dry etching, a laser grooving process or any other
desired process. At step 504, dams 520 are attached to notched
substrate 517. Dams 420 may be attached to notched substrate 517
using any desired methods or materials. For example, dams 520 may
be attached to notched substrate 517 using adhesive, glue, epoxy,
polymer, or any other desired material. Also at step 504, vias 524
may be formed in wafer 518. Vias 524 may provide a vertical
electrical connection that passes completely through wafer 518. In
embodiments where wafer 518 is made of silicon, vias 524 may be
known as through-silicon vias (TSV). Vias 524 may be electrically
connected to an image sensor integrated circuit.
[0070] At step 504, vias 524 may be provided with redistribution
layers 525. While vias 524 may extend vertically through waver 518,
redistribution layers 525 may be conductive layers that connect to
vias 524 and extend horizontally across the top surface of wafer
518. Redistribution layers 525 may be formed with a seed layer of
conductive material such as a metal. The seed layer may be
titanium, titanium-tungsten, copper, or any other desired
conductive material. Redistribution layers 525 may then have a
conductive material such as a metal plated on the seed layer. The
plated conductive material may be copper, nickel, aluminum, or any
other desired conductive material. Redistribution layers 525 may
extend the amount of area available for forming solder connections.
Redistribution layers 525 may have solder pads for forming solder
connections. The solder pads may be tin-lead plated copper pads,
silver plated copper pads, gold plated copper pads, or any other
desired type of solder pad.
[0071] Dams 520 may be formed from any desired material and have
any desired dimensions. In FIG. 7, notched substrate 517 is shown
with four attached dams. This example is merely illustrative.
Notched substrate 517 may be attached to one dam, two dams, ten
dams, hundreds of dams, or more than hundreds of dams. Substrate
517 may be attached to any desired number of dams for each sensor
die in wafer 518. For example, substrate 517 may be attached to two
dams for each sensor die in wafer 518.
[0072] At step 506, wafer 518 may be attached to dams 520. Wafer
518 may be attached to dams 520 such that each sensor die is
attached to two dams, with one dam on each side of the sensor die.
Wafer 518 may be attached to the dams using adhesive, glue, epoxy,
polymer, or any other desired material. At step 506, wafer 518 has
yet to be separated into individual sensor dies. In certain
embodiments, dams 520 may be formed from an adhesive material. In
embodiments where dams 520 are formed from an adhesive material,
the transparent substrate may be attached to the dams without using
an additional material. Similarly, the sensor dies may be attached
to the dams without using an additional material.
[0073] At step 508, wafer 518 and notched substrate 517 may be
separated to form sensor dies 526 and 528 which each are attached
to a separated portion of notched substrate 517. For example,
sensor die 526 may be attached to portion 537 of notched substrate
517 and sensor die 528 may be attached to portion 538 of notched
substrate 517. After being separated, substrate portions 537 and
538 may be attached to panel 529. Sensor dies 526 and 528 and
substrate portions 537 and 538 may be separated by sawing, cutting,
or any other desired method. As shown in FIG. 7, substrate 517 may
be cut at a notched portion with a thickness 542. The smaller
thickness at the notched portion makes cutting substrate 517
easier. Panel 529 may be temporarily attached to substrate portions
537 and 538. Panel 529 may be made of a polymer or any other
desired material. Depending on the process, panel 529 may be in
wafer form or panel form.
[0074] At step 510, a molding process may be performed to
encapsulate the sensor dies and fill in the gaps between the sensor
dies. Mold 530 may fill in the gap between sensor dies 526 and 528
and may fill the areas to the sides of sensor dies 526 and 528.
[0075] Similarly, mold 530 may fill in the gap between substrate
portions 537 and 538 and may fill the areas to the sides of
substrate portions 537 and 538. As shown in FIG. 6, sensor die 526
may have a side closest to substrate 537 that is attached to dams
520. The side that is furthest from substrate 537, which may
subsequently be referred to as the top surface, may be entirely
covered by mold 530 during the molding process. Similarly, the
redistribution layers 525 may be entirely covered by mold 530
during the molding process. The mold may have a planar top surface
after step 510. Dams 520 may prevent mold 530 from reaching pixel
arrays 522.
[0076] The molding process at step 510 may consist of dispensing a
liquid compound, compression molding, or any other desired molding
process. In embodiments where a liquid compound is used for the
molding, the liquid compound may be poured in between each sensor
die. The liquid compound may fill in all areas without penetrating
through dams 520. The liquid compound may later be cured to provide
a hermetic seal that prevents outside materials from reaching pixel
array 522. In embodiments where compression molding is used, a mold
material such as plastic may be heated at a suitable temperature
for a suitable length of time. The mold material may then be
compressed in between sensor dies and left to cure, effectively
providing a hermetic seal in between the sensor dies.
[0077] At step 512, mold vias 532 may be formed on the top surface
of mold 530. The mold vias 532 may expose solder pads on the top
surfaces of the redistributed layers 525. Mold vias 532 may be
formed using a laser drilling process or any other desired process.
In the laser drilling process, a laser is used to make vias 532 in
mold 530.
[0078] At step 514, solder 534 may be formed in mold vias 532 on
redistribution layers 525. Solder balls 534 are formed on the top
surface of silicon dies 526 and 528. In certain embodiments, solder
balls 534 may be used to electrically connect through-silicon vias
524 to bond pads on a printed circuit board. Solder balls 534 may
be located on solder pads on redistribution layers 525.
[0079] At step 516, panel 529 may be removed. Panel 529 may be
removed using any desired process. Mold 530 may then be cut to
separate dies 526 and 528. Image sensor package 536 may have
opposing top and bottom surfaces with first and second opposing
side surfaces connecting the top and bottom surfaces.
[0080] In certain embodiments, image sensor package 536 may be
diced such that no molding material remains on the left and right
sides of sensor die 526 or substrate portion 537. In these
embodiments, the bottom surface of image sensor package 536 may
have portions formed from substrate portion 537 and portions formed
from mold material 530. The top surface of image sensor package 536
may be have portions that are formed from mold material 530 and
portions that are formed from solder 534. The side surfaces of
image sensor package 536 may have portions that are formed from
substrate 537, portions that are formed from dams 520, portions
that are formed from sensor die 526, portions that are formed from
redistribution layers 525, and portions that are formed from mold
material 530.
[0081] In certain embodiments, only one cut may be made in between
sensor dies 526 and 528 (e.g., FIG. 7). In these embodiments, the
bottom surface of image sensor package 536 may have portions formed
from substrate portion 537 and portions formed from mold material
330. The top surface of image sensor package 536 may be have
portions that are formed from mold material 530 and portions that
are formed from solder 534. The side surfaces may be formed
entirely from mold material 530.
[0082] FIG. 8 shows in simplified form a typical processor system
600 which includes an imaging device 612. Imaging device 612 may
include a pixel array 614 formed on an image sensor package such as
image sensor package 136, image sensor package 236, image sensor
package 336, image sensor package 436, or image sensor package 536.
Without being limiting, such processor system 600 may include a
computer system, still or video camera system, scanner, machine
vision, vehicle navigation, video phone, surveillance system, auto
focus system, star tracker system, motion detection system, image
stabilization system, and other systems employing an imaging
device.
[0083] Processor system 600, which may be a digital still or video
camera system, may include a lens such as lens 616 for focusing an
image onto a pixel array such as pixel array 614 when shutter
release button 602 is pressed. Processor system 600 may include a
central processing unit such as central processing unit (CPU) 604.
CPU 604 may be a microprocessor that controls camera functions and
one or more image flow functions and communicates with one or more
input/output (I/O) devices 610 over a bus such as bus 618. Imaging
device 612 may also communicate with CPU 604 over bus 618. System
600 may include random access memory (RAM) 606 and removable memory
608. Removable memory 608 may include flash memory that
communicates with CPU 604 over bus 618.
[0084] Although bus 618 is illustrated as a single bus, it may be
one or more buses or bridges or other communication paths used to
interconnect the system components.
[0085] Various embodiments have been described illustrating methods
of forming image sensor packages. The method may including
attaching a plurality of dam structures to a transparent substrate,
forming a plurality of conductive vias in an image sensor wafer
having first and second image sensor dies, attaching the image
sensor wafer to the plurality of dam structures, separating the
sensor wafer into the first and second image sensor dies after
attaching the image sensor wafer to the plurality of dam
structures, attaching the first and second image senor dies to an
additional substrate, and performing a molding process. Performing
the molding process may include forming mold material on the
additional substrate in between the first and second image sensor
dies.
[0086] Attaching the image sensor wafer to the plurality of dam
structures may include attaching the first image sensor die to
first and second dam structures of the plurality of dam structures
and attaching the second image sensor die to third and fourth dam
structures of the plurality of dam structures. The first sensor die
may be attached to a first portion of a transparent substrate and
the second sensor die may be attached to a second portion of the
transparent substrate. The first and second sensor dies may be
attached to the additional substrate by attaching the first and
second portions of the transparent substrate to the additional
substrate. Forming mold material on the additional substrate may
include forming mold material in between the first and second
portions of the transparent substrate.
[0087] The method may also include removing the additional
substrate after performing the molding process. After the
additional substrate is removed, the first and second image sensor
dies may be separated to form first and second image sensor
packages. Separating the first and second image sensor dies may
include cutting the mold material that is formed between the first
and second image sensor dies.
[0088] The method may also include forming at least one conductive
layer on a surface of the sensor wafer before attaching the sensor
wafer to the plurality of dam structures. The at least one
conductive layer may be electrically and mechanically connected to
at least one conductive via of the plurality of conductive vias
previously formed in the image sensor wafer. The transparent
substrate may be a glass substrate, a notched transparent
substrate, or a notched glass substrate. In embodiments where the
transparent substrate is a notched transparent substrate and the
notched transparent substrate is cut, the notched transparent
substrate may be cut at a notch.
[0089] In certain embodiments, the method of forming image sensor
packages may include attaching an attachment structure to a
transparent substrate. The attachment structure may have first,
second, third, and fourth portions. The method may also include
forming a plurality of conductive vias in an image sensor wafer
having first and second image sensor dies and forming at least one
conductive layer on a surface of the image sensor wafer. The method
may include attaching the first image sensor die to the first and
second portions of the attachment structure and attaching the
second image sensor die to the third and fourth portions of the
attachment structure after forming the at least one conductive
layer on the surface of the image sensor wafer. A molding process
may be performed that includes forming mold material in between the
first and second image sensor dies. The top surface of the mold
material may cover the at least one conductive layer and the
surface of the image sensor wafer.
[0090] The method may also include forming at least one hole in the
top surface of the mold to expose the at least one conductive layer
that exposes a solder pad on the at least one conductive layer and
forming solder in the at least one hole. Forming the at least one
hole may be completed using laser drilling.
[0091] In certain embodiments, the method of forming image sensor
packages may include attaching a first dam, a second dam, a third
dam, and a fourth dam to a transparent substrate and forming a
plurality of conductive vias in a sensor wafer that comprises first
and second image sensor dies. Each of the first and second image
sensor dies may have at least one conductive via of the plurality
of conductive vias. The method may also include separating the
first and second image sensor dies, attaching the first image
sensor die to the first and second dam and attaching the second
image sensor die to the third and fourth dams after separating the
first and second image sensor dies, and performing a molding
process.
[0092] The molding process may include forming a mold material in
between the first and second image sensor dies. The method may also
include cutting the transparent substrate and the mold material to
form first and second image sensor packages.
[0093] After performing the molding process, a plurality of
conductive layers may be formed on the first and second image
sensor dies. Each of the plurality of conductive layers may be
electrically and mechanically connected to a respective one of the
plurality of conductive vias. A passivation layer may be formed
over the conductive layers. At least one of the conductive layers
may extend onto the mold material in between the first and second
image sensor dies.
[0094] The foregoing is merely illustrative of the principles of
this invention and various modifications can be made by those
skilled in the art. The foregoing embodiments may be implemented
individually or in any combination.
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